114 University of California Publications in Geology [ V ° L - 10 



sandstones and gravels, and clay strata. The sandstones are coarse 

 and the grains exhibit markedly the effects of water wear. The con- 

 glomerate pebbles and boulders are well rounded and polished. The 

 formation has a thickness of perhaps one hundred feet. These beds 

 lie with marked unconformity upon the Monterey and contain a 

 marine fauna determined by Dr. Clark to be the "Santa Margarita" 

 stage of the upper Miocene. At the northern end of the area these 

 beds have been more sharply deformed than the Monterey where it 

 is known in this area, so that they dip away from the crystalline rocks 

 at angles of 25 degrees or more. 



The uppermost stratigraphic member in the Tejon Hills extends 

 from the northwest end of the hills over almost the entire remaining 

 territory excepting a small area of crystalline rocks exposed at the 

 point where Tejon Creek enters the hills, and along Chanae Creek. 

 Areally this uppermost member is the most important terrane of the 

 Tejon Hills.- In view of their distinctiveness in lithologic character 

 and in mode of origin the name Chanae formation is proposed for these 

 strata. Lithologieally this formation consists of angular sands and 

 coarser angular materials. The particles are mainly rhyolitic and 

 display white, yellow and striking reddish-brown colors in exposures. 

 The materials are not well classified as to size and are not sharply 

 bedded. Their characters are altogether those of a terrestrial deposit 

 of the alluvial fan type, and they should be termed fanglomerates. 

 Their thickness is estimated to be four hundred to six hundred feet. 

 The Chanae fanglomerates rest upon both of the older Tertiary 

 formations and in the southern part of the Tejon Hills upon the old 

 crystalline rocks. From the geologic evidence it seems probable that 

 they bear an unconformable relation to the beds they overlie, but the 

 evidence does not appear conclusive. The distinctly different char- 

 acter of the materials and of the faunas of the Chanae contrasted with 

 the underlying formations, indicates a change from marine conditions 

 to the terrestrial conditions, and favors the view of unconformity. 

 Theoretically, such changes might be the result of the filling of a 

 marine basin and the deposition, without interruption, of terrestrial 

 beds upon the marine strata. The areal relations, however, suggest 

 unconformity, although no discordance was observed in the attitude of 

 the strata of the Chanae and "Santa Margarita," and no pre-Chanac 

 surface of erosion. 



